Engineered ribosomal RNA operon copy-number variants of E. coli reveal the evolutionary trade-offs shaping rRNA operon number.

ABSTRACT: Ribosomal RNA (rrn) operons, characteristically present in several copies in bacterial genomes (7 in E. coli), play a central role in cellular physiology. We investigated the factors determining the optimal number of rrn operons in E. coli by constructing isogenic variants with 5-10 operons. We found that the total RNA and protein content, as well as the size of the cells reflected the number of rrn operons. While growth parameters showed only minor differences, competition experiments revealed a clear pattern: 7-8 copies were optimal under conditions of fluctuating, occasionally rich nutrient influx and lower numbers were favored in stable, nutrient-limited environments. We found that the advantages of quick adjustment to nutrient availability, rapid growth and economic regulation of ribo

SUBMITTER: Gyorfy Z 

PROVIDER: S-EPMC4330394 | biostudies-literature | 2015 Feb

REPOSITORIES: biostudies-literature